cel-expr · copybara-service · Oct 2, 2026
diff --git a/common/src/main/java/dev/cel/common/values/BUILD.bazel b/common/src/main/java/dev/cel/common/values/BUILD.bazel
@@ -320,6 +320,7 @@ java_library(
         "ProtoLiteCelValueConverter.java",
         "ProtoMessageLiteValue.java",
         "RawProtoMessageLiteValue.java",
+        "WireMessageLite.java",
     ],
     tags = [
     ],
@@ -350,6 +351,7 @@ cel_android_library(
         "ProtoLiteCelValueConverter.java",
         "ProtoMessageLiteValue.java",
         "RawProtoMessageLiteValue.java",
+        "WireMessageLite.java",
     ],
     tags = [
     ],

diff --git a/common/src/main/java/dev/cel/common/values/ProtoLiteCelValueConverter.java b/common/src/main/java/dev/cel/common/values/ProtoLiteCelValueConverter.java
@@ -29,7 +29,6 @@
 import com.google.protobuf.CodedInputStream;
 import com.google.protobuf.ExtensionRegistryLite;
 import com.google.protobuf.MessageLite;
-import com.google.protobuf.MessageLiteOrBuilder;
 import com.google.protobuf.WireFormat;
 import dev.cel.common.annotations.Internal;
 import dev.cel.common.internal.CelLiteDescriptorPool;
@@ -45,7 +44,6 @@
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.NoSuchElementException;
 import java.util.Optional;
 import java.util.TreeMap;
 
@@ -110,6 +108,8 @@ private static Object readFixed32BitField(
       case FLOAT:
         return inputStream.readFloat();
       case FIXED32:
+        return UnsignedLong.fromLongBits(
+            Integer.toUnsignedLong(inputStream.readRawLittleEndian32()));
       case SFIXED32:
         return inputStream.readRawLittleEndian32();
       default:
@@ -124,6 +124,7 @@ private static Object readFixed64BitField(
       case DOUBLE:
         return inputStream.readDouble();
       case FIXED64:
+        return UnsignedLong.fromLongBits(inputStream.readRawLittleEndian64());
       case SFIXED64:
         return inputStream.readRawLittleEndian64();
       default:
@@ -171,31 +172,21 @@ Optional<FieldLiteDescriptor> findFieldDescriptor(String protoTypeName, int fiel
         .flatMap(desc -> desc.findByFieldNumber(fieldNumber));
   }
 
-  Optional<Object> tryDecodeWellKnownProto(ByteString bytes, String protoTypeName) {
-    Optional<WellKnownProto> wellKnownProto = WellKnownProto.getByTypeName(protoTypeName);
-    if (!wellKnownProto.isPresent()) {
-      return Optional.empty();
-    }
-
+  Optional<Object> tryDecodeProtoMessage(ByteString bytes, String protoTypeName) {
     return descriptorPool
         .findDescriptor(protoTypeName)
-        .map(
-            descriptor ->
-                decodeWellKnownProto(bytes, protoTypeName, descriptor, wellKnownProto.get()));
+        .map(descriptor -> decodeProtoMessage(bytes, protoTypeName, descriptor));
   }
 
-  private Object decodeWellKnownProto(
-      ByteString bytes,
-      String protoTypeName,
-      MessageLiteDescriptor descriptor,
-      WellKnownProto wellKnownProto) {
+  private Object decodeProtoMessage(
+      ByteString bytes, String protoTypeName, MessageLiteDescriptor descriptor) {
     try {
-      MessageLite.Builder builder = descriptor.newMessageBuilder();
-      builder.mergeFrom(bytes, ExtensionRegistryLite.getEmptyRegistry());
-      return fromWellKnownProto(builder.build(), wellKnownProto);
+      MessageLite.Builder builder =
+          descriptor.newMessageBuilder().mergeFrom(bytes, ExtensionRegistryLite.getEmptyRegistry());
+      return toRuntimeValue(builder.build(), descriptor);
     } catch (IOException e) {
       throw new IllegalArgumentException(
-          "Failed to decode well-known proto of type: " + protoTypeName, e);
+          "Failed to decode proto message of type: " + protoTypeName, e);
     }
   }
 
@@ -209,35 +200,21 @@ public Object toRuntimeValue(Object value) {
       if (descriptor == null) {
         return RawProtoMessageLiteValue.create(msg.toByteString(), this);
       }
-      WellKnownProto wellKnownProto =
-          WellKnownProto.getByTypeName(descriptor.getProtoTypeName()).orElse(null);
-
-      if (wellKnownProto == null) {
-        return ProtoMessageLiteValue.create(msg, descriptor.getProtoTypeName(), this);
-      }
-
-      return fromWellKnownProto(msg, wellKnownProto);
+      return toRuntimeValue(msg, descriptor);
     }
 
     return super.toRuntimeValue(value);
   }
 
-  @Override
-  protected Object fromWellKnownProto(MessageLiteOrBuilder msg, WellKnownProto wellKnownProto) {
-    if (wellKnownProto == WellKnownProto.FIELD_MASK) {
-      MessageLite message = (MessageLite) msg;
-      MessageLiteDescriptor descriptor =
-          descriptorPool
-              .findDescriptor(message)
-              .orElseThrow(
-                  () ->
-                      new NoSuchElementException(
-                          "Could not find a descriptor for message of type: "
-                              + message.getClass().getName()));
-      return ProtoMessageLiteValue.create(message, descriptor.getProtoTypeName(), this);
+  private Object toRuntimeValue(MessageLite msg, MessageLiteDescriptor descriptor) {
+    WellKnownProto wellKnownProto =
+        WellKnownProto.getByTypeName(descriptor.getProtoTypeName()).orElse(null);
+
+    if (wellKnownProto == null || wellKnownProto == WellKnownProto.FIELD_MASK) {
+      return ProtoMessageLiteValue.create(msg, descriptor.getProtoTypeName(), this);
     }
 
-    return super.fromWellKnownProto(msg, wellKnownProto);
+    return fromWellKnownProto(msg, wellKnownProto);
   }
 
   private Object getDefaultValue(FieldLiteDescriptor fieldDescriptor) {
@@ -257,11 +234,13 @@ private Object getScalarDefaultValue(FieldLiteDescriptor fieldDescriptor) {
     JavaType type = fieldDescriptor.getJavaType();
     switch (type) {
       case INT:
-        return fieldDescriptor.getProtoFieldType().equals(FieldLiteDescriptor.Type.UINT32)
+        return (fieldDescriptor.getProtoFieldType().equals(FieldLiteDescriptor.Type.UINT32)
+                || fieldDescriptor.getProtoFieldType().equals(FieldLiteDescriptor.Type.FIXED32))
             ? UnsignedLong.ZERO
             : Defaults.defaultValue(long.class);
       case LONG:
-        return fieldDescriptor.getProtoFieldType().equals(FieldLiteDescriptor.Type.UINT64)
+        return (fieldDescriptor.getProtoFieldType().equals(FieldLiteDescriptor.Type.UINT64)
+                || fieldDescriptor.getProtoFieldType().equals(FieldLiteDescriptor.Type.FIXED64))
             ? UnsignedLong.ZERO
             : Defaults.defaultValue(long.class);
       case ENUM:

diff --git a/common/src/main/java/dev/cel/common/values/ProtoMessageLiteValue.java b/common/src/main/java/dev/cel/common/values/ProtoMessageLiteValue.java
@@ -52,7 +52,7 @@
  */
 @AutoValue
 @Immutable
-public abstract class ProtoMessageLiteValue extends StructValue<String, MessageLite>
+abstract class ProtoMessageLiteValue extends StructValue<String, MessageLite>
     implements OptimizedSelectable {
 
   @Override
@@ -142,7 +142,7 @@ public Optional<Object> findByFieldNumber(SelectField field) {
         .orElse(null);
   }
 
-  public static ProtoMessageLiteValue create(
+  static ProtoMessageLiteValue create(
       MessageLite value, String typeName, ProtoLiteCelValueConverter protoLiteCelValueConverter) {
     checkNotNull(value);
     checkNotNull(typeName);

diff --git a/common/src/main/java/dev/cel/common/values/RawProtoMessageLiteValue.java b/common/src/main/java/dev/cel/common/values/RawProtoMessageLiteValue.java
@@ -30,7 +30,6 @@
 import com.google.protobuf.ByteString;
 import com.google.protobuf.CodedInputStream;
 import com.google.protobuf.WireFormat;
-import dev.cel.common.annotations.Internal;
 import dev.cel.common.exceptions.CelAttributeNotFoundException;
 import dev.cel.common.types.CelType;
 import dev.cel.common.types.StructTypeReference;
@@ -39,6 +38,7 @@
 import java.util.AbstractMap;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Optional;
 import java.util.TreeMap;
@@ -49,38 +49,63 @@
  * client-server version skew issues where newer fields or submessages lack generated classes and
  * descriptors in the evaluation environment.
  *
- * <p>Rather than requiring compiled {@link MessageLite} classes or runtime schema descriptors, this
+ * <p>Rather than requiring compiled {@code MessageLite} classes or runtime schema descriptors, this
  * value encapsulates the raw wire-format {@link ByteString} payload and performs classless,
  * reflection-free field traversal directly over wire tags via {@link CodedInputStream}.
  */
 @AutoValue
 @AutoValue.CopyAnnotations
 @Immutable
 @SuppressWarnings("Immutable") // Immutable wire fields
-@Internal
-public abstract class RawProtoMessageLiteValue extends StructValue<String, RawProtoMessageLiteValue>
-    implements OptimizedSelectable {
+abstract class RawProtoMessageLiteValue extends StructValue<String, WireMessageLite>
+    implements OptimizedSelectable, WireMessageLite {
 
   private static final String UNKNOWN_MESSAGE_TYPE_NAME = "cel.@unknownMessage";
   private static final int MAP_KEY_FIELD_NUMBER = 1;
   private static final int MAP_VALUE_FIELD_NUMBER = 2;
 
-  abstract ByteString rawWireBytes();
+  @Override
+  public abstract ByteString toByteString();
 
   @Override
   public abstract CelType celType();
 
   abstract ProtoLiteCelValueConverter protoLiteCelValueConverter();
 
   @Override
-  public RawProtoMessageLiteValue value() {
+  public String protoTypeName() {
+    return celType().name();
+  }
+
+  @Override
+  public WireMessageLite value() {
     return this;
   }
 
+  @Override
+  public final boolean equals(Object other) {
+    // TODO: Support message equality
+    throw new UnsupportedOperationException("Message equality is not supported");
+  }
+
+  @Override
+  public final int hashCode() {
+    throw new UnsupportedOperationException("Message equality is not supported");
+  }
+
+  @Override
+  public final String toString() {
+    return String.format(
+        Locale.US,
+        "WireMessageLite{protoTypeName=%s, size=%d}",
+        protoTypeName(),
+        toByteString().size());
+  }
+
   @Memoized
   ImmutableListMultimap<Integer, Object> unknownFields() {
     try {
-      CodedInputStream inputStream = rawWireBytes().newCodedInput();
+      CodedInputStream inputStream = toByteString().newCodedInput();
       Multimap<Integer, Object> fields = Multimaps.newMultimap(new TreeMap<>(), ArrayList::new);
       for (int tag = inputStream.readTag(); tag != 0; tag = inputStream.readTag()) {
         int tagWireType = WireFormat.getTagWireType(tag);
@@ -96,7 +121,7 @@ ImmutableListMultimap<Integer, Object> unknownFields() {
 
   @Override
   public boolean isZeroValue() {
-    return rawWireBytes().isEmpty();
+    return toByteString().isEmpty();
   }
 
   /**
@@ -169,27 +194,15 @@ private static Object decodeWireField(
     }
 
     boolean isRepeated = field.defaultValue() instanceof List;
-    String protoTypeName = resolveProtoTypeName(field);
-
-    return decodeWireEntries(unknowns, typeCode, protoTypeName, isRepeated, converter);
-  }
 
-  /**
-   * Resolves the protobuf message type name for a field from the optimizer metadata in {@link
-   * SelectField}, or {@link #UNKNOWN_MESSAGE_TYPE_NAME} if unspecified.
-   */
-  private static String resolveProtoTypeName(SelectField field) {
-    if (!field.protoTypeName().isEmpty()) {
-      return field.protoTypeName();
-    }
-    return UNKNOWN_MESSAGE_TYPE_NAME;
+    return decodeWireEntries(unknowns, typeCode, field.protoTypeName(), isRepeated, converter);
   }
 
   private static Object resolveDefault(SelectField field, ProtoLiteCelValueConverter converter) {
     if (field.defaultValue() != null) {
       return field.defaultValue();
     }
-    return create(ByteString.EMPTY, resolveProtoTypeName(field), converter);
+    return decodeMessageValue(ByteString.EMPTY, field.protoTypeName(), converter);
   }
 
   /**
@@ -419,9 +432,7 @@ static Object decodeWireValue(
         throw new UnsupportedOperationException("Groups are not supported");
       case MESSAGE:
         ByteString msgBytes = requireType(raw, ByteString.class, fieldType);
-        return converter
-            .tryDecodeWellKnownProto(msgBytes, protoTypeName)
-            .orElseGet(() -> create(msgBytes, protoTypeName, converter));
+        return decodeMessageValue(msgBytes, protoTypeName, converter);
       case BYTES:
         return CelByteString.of(requireType(raw, ByteString.class, fieldType).toByteArray());
       case UINT32:
@@ -437,6 +448,13 @@ static Object decodeWireValue(
     throw new IllegalArgumentException("Unsupported proto field type: " + fieldType);
   }
 
+  private static Object decodeMessageValue(
+      ByteString msgBytes, String protoTypeName, ProtoLiteCelValueConverter converter) {
+    return converter
+        .tryDecodeProtoMessage(msgBytes, protoTypeName)
+        .orElseGet(() -> create(msgBytes, protoTypeName, converter));
+  }
+
   private static <T> T requireType(
       Object raw, Class<T> expectedType, WireFormat.FieldType fieldType) {
     if (!expectedType.isInstance(raw)) {
@@ -509,12 +527,12 @@ private static ImmutableList<Object> decodePacked(
     }
   }
 
-  public static RawProtoMessageLiteValue create(
+  static RawProtoMessageLiteValue create(
       ByteString rawWireBytes, ProtoLiteCelValueConverter protoLiteCelValueConverter) {
     return create(rawWireBytes, "", protoLiteCelValueConverter);
   }
 
-  public static RawProtoMessageLiteValue create(
+  static RawProtoMessageLiteValue create(
       ByteString rawWireBytes,
       String protoTypeName,
       ProtoLiteCelValueConverter protoLiteCelValueConverter) {

diff --git a/common/src/main/java/dev/cel/common/values/WireMessageLite.java b/common/src/main/java/dev/cel/common/values/WireMessageLite.java
@@ -0,0 +1,47 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package dev.cel.common.values;
+
+import com.google.errorprone.annotations.Immutable;
+import com.google.protobuf.ByteString;
+import dev.cel.common.annotations.Beta;
+
+/**
+ * Represents a protobuf message evaluation result in {@code CelLiteRuntime} when no {@code
+ * CelLiteDescriptor} is registered for the message type.
+ *
+ * <p>When a message-typed expression is evaluated in {@code CelLiteRuntime}:
+ *
+ * <ul>
+ *   <li>If a {@code CelLiteDescriptor} is registered for the message type, evaluation produces a
+ *       {@code MessageLite} instance.
+ *   <li>Otherwise, evaluation produces a {@code WireMessageLite} carrying the message's protobuf
+ *       type name and wire-encoded payload.
+ * </ul>
+ */
+@Immutable
+@Beta
+public interface WireMessageLite {
+
+  /**
+   * Returns the fully-qualified protobuf message type name (e.g. {@code
+   * "cel.expr.conformance.proto3.TestAllTypes.NestedMessage"}), or {@code "cel.@unknownMessage"} if
+   * the message type name is not known at runtime.
+   */
+  String protoTypeName();
+
+  /** Serializes the message to a {@link ByteString} in protobuf wire format. */
+  ByteString toByteString();
+}